--- symmetry.pl	2007/08/26 14:45:26	7
+++ symmetry.pl	2007/08/31 14:23:21	10
@@ -119,6 +119,7 @@
 my $ok_path = qr/[\|\-]/;
 
 my @corners;
+my $corners_usage;
 
 sub can_turn {
 	my $try_step = shift;
@@ -135,10 +136,11 @@
 	$trace[ $turn_pos ] = $old;
 
 	if ( $board[ $turn_pos ] =~ $ok_path ) {
-		my $xy = x_y($turn_pos);
-		warn "OK can_turn $try_step $step_name[$try_step] turn_pos = $turn_pos b($board[$turn_pos]) t($trace[$turn_pos]) to $xy\n";
+		my $xy = x_y($pos);
+		warn "OK can_turn $try_step $step_name[$try_step] turn_pos = $turn_pos b($board[$turn_pos]) t($trace[$turn_pos]) from $xy\n";
 		$step = $try_step;
 		push @corners, $xy;
+		$corners_usage->{$xy}++;
 		return 1;
 	} else {
 		warn "NOPE can_turn $try_step $step_name[$try_step] turn_pos = $turn_pos b($board[$turn_pos]) t($trace[$turn_pos])\n";
@@ -170,7 +172,14 @@
 	my $len = 0;
 	$step = 0;
 
-	warn "<<< shape from $x,$y pos: $pos\n";
+	my $usage = $corners_usage->{"$x,$y"} || 0;
+
+	warn "<<< shape from $x,$y [usage: $usage] pos: $pos\n";
+
+	if ( $usage > 4 ) {
+		warn "SKIPPED, usage > 4\n";
+		return;
+	}
 
 	while( 1 ) {
 
@@ -198,7 +207,7 @@
 
 	push @shapes_found, { x => $x, y => $y, len => $len, directions => show_directions };
 
-	warn "### corners: ",join(' ', @corners),"\n";
+	warn "### corners: ",join(' ', map { $_ . " [" . $corners_usage->{$_} . "]" } @corners),"\n";
 	warn ">>> ended at $pos, line length: $len, directions traversed: ",show_directions,"\n";
 
 	foreach my $c ( @corners ) {
@@ -223,7 +232,20 @@
 	}
 }
 
+sub is_symmetric {
+	my $path = shift || die "no path?";
+
+	my $h = length($path)/2;
+	return 0 if int($h) != $h;
+	my ($l,$r) = ( substr($path,0,$h), substr($path,$h) );
+	$r =~ tr/lrud/rldu/;
+#	warn "$l -- $r\n";
+	return 0 unless $l eq $r;
+	return 1;
+}
+
 print ">>> RESULTS:\n";
 foreach my $r ( @shapes_found ) {
-	printf "%2d,%-2d len: %-4d directions: %s\n", $r->{x}, $r->{y}, $r->{len}, $r->{directions};
+	printf "%2d,%-2d len: %-4d directions: %s %s\n",
+	$r->{x}, $r->{y}, $r->{len}, $r->{directions}, is_symmetric($r->{directions}) ? 'symetric' : '';
 }